Here is my first video using Version 6: https://www.youtube.com/watch?v=XNCQpvGXOtk
I noticed some issues. First, the rendering time is slower than before. It took about 20 minutes to render that video at 30 FPS. It's not terrible but a bit slower than previous versions.
I also noticed an issue where the graphical piano plays extra notes while the bar note is still holding. Look at Middle C during the first 10 seconds of my video.
Here's the MIDI file for it: https://drive.google.com/file/d/10xnEs50SLLRPbjDdQcu0F1jVGwYSOt2n/view?usp=sharing